Stacked chip layout having overlapped regions

ABSTRACT

A stacked chip layout includes a central processing chip; and a first active circuit block over the central processing chip. The stacked chip layout further includes a second active circuit block over the first active circuit. A center of the second active circuit block is offset from a center of the first active circuit block, the second active circuit block overlaps the first active circuit block in a partial overlap area, and the second active circuit block exposes a portion of the first active circuit block. The stacked chip layout further includes a local conductive element electrically connecting the first active circuit block to the second active circuit block. The local conductive element is within the partial overlap area.

PRIORITY CLAIM

The present application is a continuation of U.S. application Ser. No.14/855,494, filed Sep. 16, 2015, which is a divisional of U.S.application Ser. No. 14/015,262, filed Aug. 30, 2013, now U.S. Pat. No.9,159,716, issued Oct. 13, 2015, which are incorporated herein byreference in their entireties.

BACKGROUND

Packaging arrangements for multiple active circuit blocks are used toprovide electrical connection between the active circuit blocks. Atwo-dimensional (2D) packaging arrangement has a central processing chipalong with one or more active circuit blocks arranged on a same plane ina two-dimensional layout. The 2D packaging arrangement includeselectrical routing for transferring signals between the active circuitblocks and between an active circuit block and the central processingchip on a same plane as the active circuit blocks.

A 2.5D packaging arrangement includes the central processing chip on afirst plane and each of the active circuit blocks on a second planedifferent from the first plane. Electrical routing for transferringsignals between the active circuit blocks is present in both planes ofthe 2.5D packaging arrangement.

A three dimensional (3D) packaging arrangement has the centralprocessing chip and each active circuit block on a separate plane. Asize of the active circuit blocks is artificially increased so that anarea of the active circuit block substantially matches an area of thecentral processing chip. The size increase of the active circuit blocksdoes not increase a number of active elements within an active circuitblock. The increased size is used to enable electrical routing totransfer signals between the various active circuit blocks and thecentral processing chip. The electrical routing lines from one plane toanother pass through intervening active circuit blocks between activeelements within the active circuit block.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments are illustrated by way of example, and not bylimitation, in the figures of the accompanying drawings, whereinelements having the same reference numeral designations represent likeelements throughout. It is emphasized that, in accordance with standardpractice in the industry various features may not be drawn to scale andare used for illustration purposes only. In fact, the dimensions of thevarious features in the drawings may be arbitrarily increased or reducedfor clarity of discussion.

FIG. 1 is a perspective view of a stacked chip layout including fouractive circuit blocks in accordance with one or more embodiments;

FIG. 2 is a top view of the stacked chip layout of FIG. 1 in accordancewith one or more embodiments;

FIG. 3 is a top view of the stacked chip layout of FIG. 1 includingpartial overlap and full overlap areas in accordance with one or moreembodiments;

FIG. 4 is a cross sectional view of the stacked chip layout of FIG. 1including an enlarged cross sectional view of a routing area inaccordance with one or more embodiments;

FIG. 5 is a cross sectional view of the stacked chip layout of FIG. 1 inaccordance with one or more embodiments;

FIG. 6 is a cross sectional view of the stacked chip layout of FIG. 1including a central clocking tree in accordance with one or moreembodiments;

FIGS. 7A and 7B are perspective views of electrical connections betweenvarious active circuit blocks of the stacked chip layout of FIG. 1 inaccordance with one or more embodiments;

FIG. 8A is a perspective view of electrical connections between variousactive circuit blocks of the stacked chip layout of FIG. 1 in accordancewith one or more embodiments;

FIG. 8B is a cross sectional view of electrical connections betweenvarious active circuit blocks of the stacked chip layout of FIG. 1 inaccordance with one or more embodiments;

FIG. 9 is a perspective view of a stacked chip layout including eightactive circuit blocks in accordance with one or more embodiments;

FIG. 10 is a perspective view of a stacked chip layout including eightactive circuit blocks in accordance with one or more embodiments; and

FIG. 11 is a flow chart of a method of making a stacked chip layout inaccordance with one or more embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are examples and are not intended to belimiting.

Challenges which impact packaging of multiple active circuit blocks intoa single structure include routing of interconnect lines between theactive circuit blocks, routing of power lines to the active circuitblocks and dissipation of heat generated by the active circuit blocks.As technology nodes shrink, a size of the active circuit blocksdecrease; however, a number of active elements within each activecircuit block remains unchanged, in some embodiments. Due to the numberof active elements remaining constant, a number of connections betweenthe active circuit blocks also remain constant.

The decreased active circuit block size in conjunction with the constantnumber of connections increases a complexity of routing of theelectrical signals between active circuit blocks and between the activecircuit blocks and a central processing chip. In some 2D packagingarrangements, an overall area of the package is increased to enablerouting of interconnect structures between the various active circuitblocks. The overall area of the 2D packaging arrangement is increased toprovide adequate spacing between signal lines and power lines to reduceinterference and cross talk between the lines. The increase in theoverall area also increases a length of the conductive lines carryingthe signals between components which introduce errors into the signals,in some instances.

In some 2.5D packaging arrangements, a complexity of the interconnectstructure routings are increased. In some instances, modifications tothe active circuit block are used to enable placement of the activecircuit block in a desired location on the packaging arrangement. As aresult, complexity of design and production costs increase due to thecomplexity of the interconnect structure.

In some 3D packaging arrangements, interconnect structures are routedbetween active elements of the active circuit blocks. Currents passingthrough interconnect structures interfere with operation of the activeelements, in some instances. A higher current through the interconnectstructure increases a risk of interference with the active elements. Asa result, large spacing between interconnect structures and the activeelements are maintained to reduce the risk of interference. The largespacing used in the 3D packaging arrangement increases the length of theinterconnect structures which impacts timing of the active circuitblock, in some instances. The risk of interference also restricts anamount of current which is applied through a power line used to powerthe various active circuit blocks. The power line current restrictionsresult in an increase in a number of power lines used to providesufficient power to operate the various active circuit blocks or anincrease in a number of separate active circuit block stacks to providea same function, in some instances.

Some 3D packaging arrangements also experience problems with dissipatingheat generated during operation of the various active circuit blocks. Bystacking the active circuit blocks directly on top of one another, heatgenerated during operation is trapped and negatively impacts performanceof the active circuit blocks, in some instances.

FIG. 1 is a perspective view of a stacked chip layout 100 including fouractive circuit blocks in accordance with one or more embodiments. Chiplayout 100 includes a central processing chip 102 having a first area.Chip layout 100 further includes a first active circuit block 104containing active elements disposed over central processing chip 102.First active circuit block 104 has a second area less than the firstarea of central processing chip 102. Chip layout 100 further includes asecond active circuit block 106 over first active circuit block 104.Second active circuit block 106 partially overlaps with first activecircuit block 104, but does not fully overlap with the first activecircuit block. Second active circuit block 106 has a third area lessthan the first area of central processing chip 102. Chip layout 100further includes a third active circuit block 108 over second activecircuit block 106. Third active circuit block 108 partially overlapswith second active circuit block 106, but does not fully overlap withthe second active circuit block. Third active circuit block 108 doesalso partially overlaps with first active circuit block 104. A portionof third active circuit block 108 overlaps with both second activecircuit block 106 and first active circuit block 104. Third activecircuit block 108 has a fourth area less than the first area of centralprocessing chip 102. Chip layout 100 further includes a fourth activecircuit block 110 over third active circuit block 108. Fourth activecircuit block 110 partially overlaps with third active circuit block108, but does not fully overlap with the third active circuit block.Fourth active circuit block 110 also partially overlaps with firstactive circuit block 104. Fourth active circuit block 110 also partiallyoverlaps with second active circuit block 106. A portion of fourthactive circuit block 110 overlaps with third active circuit block 108,second active circuit block 106 and first active circuit block 104.Fourth active circuit block 110 has a fifth area less than the firstarea of central processing chip 102.

In the arrangement of FIG. 1, each of first active circuit block 104,second active circuit block 106, third active circuit block 108 andfourth active circuit block 110 are aligned with a corner of centralprocessing chip 102. In some embodiments, at least one of first activecircuit block 104, second active circuit block 106, third active circuitblock 108 or fourth active circuit block 110 is not aligned with acorner of central processing chip 102. In the arrangement of FIG. 1,each of first active circuit block 104, second active circuit block 106,third active circuit block 108 and fourth active circuit block 110 has asame area. In some embodiments, at least one of first active circuitblock 104, second active circuit block 106, third active circuit block108 or fourth active circuit block 110 has a different area from atleast another of the other active circuit blocks.

Each of first active circuit block 104, second active circuit block 106,third active circuit block 108 and fourth active circuit block 110contain active circuitry. In some embodiments, the active circuitryincludes memory, such as dynamic random access memory (DRAM), anapplication specific integrated circuit (ASIC) or another suitableactive circuit device. Each of first active circuit block 104, secondactive circuit block 106, third active circuit block 108 and fourthactive circuit block 110 are connected to central processing chip 102.At least one of first active circuit block 104, second active circuitblock 106, third active circuit block 108 or fourth active circuit block110 is connected to at least another one of the first active circuitblock, the second active circuit block, the third active circuit blockor the fourth active circuit block.

FIG. 2 is a top view of the stacked chip layout 100 in accordance withone or more embodiments. The top view of chip layout 100 indicates thata portion of each of first active circuit block 104, second activecircuit block 106 and third active circuit block 108 is exposed byactive circuit blocks positioned above each of the first active circuitblock, the second active circuit block and the third active circuitblock. By exposing a portion of each of each of first active circuitblock 104, second active circuit block 106 and third active circuitblock 108, heat generated by the active circuit blocks is more easilydissipated in comparison with packaging arrangements which completelycover active circuit blocks, such as 3D packaging arrangements.

In the arrangement of FIG. 2, central processing chip 102 is completelycovered by the combination of first active circuit block 104, secondactive circuit block 106, third active circuit block 108 and fourthactive circuit block 110. In some embodiments, a portion of centralprocessing chip 102 is exposed by the combination of first activecircuit block 104, second active circuit block 106, third active circuitblock 108 and fourth active circuit block 110.

FIG. 3 is a top view of the stacked chip layout 100 including partialoverlap and full overlap areas in accordance with one or moreembodiments. Chip layout 100 includes four partial overlap areas 120where less than all of first active circuit block 104, second activecircuit block 106, third active circuit block 108 and fourth activecircuit block 110 overlap one another. In the arrangement of FIG. 3,partial overlap area 120 between third active circuit block 108 andfourth active circuit block 110 is larger than partial overlap area 120between the third active circuit block and second active circuit block106. In some embodiments, each partial overlap area 120 has a same size.In some embodiments, each partial overlap area 120 has a different sizefrom each other partial overlap area 120. Chip layout 100 furtherincludes a full overlap area 130. Full overlap area 130 is a place whereall of first active circuit block 104, second active circuit block 106,third active circuit block 108 and fourth active circuit block 110overlap one another.

Partial overlap areas 102 are used to provide electrical connectionsbetween the overlapping active circuit blocks. In some embodiments, theelectrical connections include inter-level vias (ILVs) formed in adielectric material. In some embodiments, the electrical connectionsinclude solder balls, copper posts or other suitable electricalconnection structures.

Full overlap area 130 is used to provide connection between all of firstactive circuit block 104, second active circuit block 106, third activecircuit block 108 and fourth active circuit block 110 along with centralprocessing chip 102. Signals which are shared by all of the activecircuit blocks are routed through full overlap area 130. A size of fulloverlap area 130 is determined based on a size and layout of the activecircuit blocks. The size of the full overlap area 130 is minimized tohelp increase an ability of chip layout 100 do dissipate heat generatedby the active circuit blocks and to facilitate routing of electricalsignals between the active circuit blocks.

FIG. 4 is a cross sectional view of the stacked chip layout 100including an enlarged cross sectional view of a routing area inaccordance with one or more embodiments. FIG. 4 is the cross sectionview along line A-A of FIG. 2 in accordance with one or moreembodiments. Chip layout 100 includes ILV layers 160 positioned betweeneach of central processing chip 102, first active circuit block 104,second active circuit block 106, third active circuit block 108 andfourth active circuit block 110. Chip layout 100 further includes afirst routing area 104 a on a same plane as first active circuit block104. First routing area 104 a has an area equal to a difference betweenthe second area of first active circuit block 104 and the first area ofcentral processing chip 102. Chip layout 100 further includes a secondrouting area 106 a on a same plane as second active circuit block 106.Second routing area 106 a has an area equal to a difference between thethird area of second active circuit block 106 and the first area ofcentral processing chip 102. Chip layout 100 further includes a thirdrouting area 108 a on a same plane as third active circuit block 108.Third routing area 108 a has an area equal to a difference between thefourth area of third active circuit block 108 and the first area ofcentral processing chip 102. Chip layout 100 further includes a fourthrouting area 110 a on a same plane as fourth active circuit block 110.Fourth routing area 110 a has an area equal to a difference between thefifth area of fourth active circuit block 110 and the first area ofcentral processing chip 102.

ILV layers 160 include a dielectric material having conductive viasformed therein. The conductive vias provide electrical connection forsignal transfer between layers of chip layout 100. In some embodiments,the dielectric material includes silicon oxide, silicon nitride, siliconcarbide, silicon oxynitride or other suitable dielectric materials. Insome embodiments, the conductive vias include copper, aluminum, alloysthereof or other suitable conductive materials.

First routing area 104 a is a dielectric material having conductivelines and/or vias formed therein. The conductive lines and or viasprovide electrical connections for signal transfer between first activecircuit block 104 and other components of chip layout 100. In someembodiments, first routing area 104 a includes conductive viasconfigured to electrically connect at least one of second active circuitblock 106, third active circuit block 108 or fourth active circuit block110 to central processing chip 102. In some embodiments, first routingarea 104 a is configured to electrically connect ILV layer 160 betweenfirst active circuit block 104 and central processing chip 102 with ILVlayer 160 between the first active circuit block and second activecircuit block 106. In some embodiments, the dielectric material of firstrouting layer 104 a includes silicon oxide, silicon nitride, siliconcarbide, silicon oxynitride or other suitable dielectric materials. Inthe embodiment of FIG. 4, the dielectric material of first routing area104 a is different from the dielectric material of ILV layer 160, sothat the dielectric materials act as etch stop layers during formationof the conductive lines and/or vias. In some embodiments, the dielectricmaterial of first routing area 104 a is a same dielectric material asthe dielectric material of ILV layers 160. In some embodiments, theconductive lines and/or vias of first routing area 104 a include copper,aluminum, alloys thereof or other suitable conductive materials. In someembodiments, the conductive vias of ILV layers 160 include a samematerial as the conductive lines and/or vias of first routing area 104a. In some embodiments, the conductive vias of ILV layers 160 include adifferent material from the conductive lines and/or vias of firstrouting area 104 a.

Second routing area 106 a is a dielectric material having conductivelines and/or vias formed therein. The conductive lines and or viasprovide electrical connections for signal transfer between second activecircuit block 106 and other components of chip layout 100. In someembodiments, second routing area 106 a includes conductive viasconfigured to electrically connect at least one of third active circuitblock 108 or fourth active circuit block 110 to central processing chip102. In some embodiments, second routing area 106 a is configured toelectrically connect ILV layer 160 between first active circuit block104 and second active layer 106 with ILV layer 160 between the secondactive circuit block and third active circuit block 108. In someembodiments, the dielectric material of second routing area 106 a is asame material as the dielectric material of first routing area 104 a. Insome embodiments, the dielectric material of second routing area 106 ais different from the dielectric material of first routing area 104 a.In the embodiment of FIG. 4, the dielectric material of second routingarea 106 a is different from the dielectric material of ILV layer 160,so that the dielectric materials act as etch stop layers duringformation of the conductive lines and/or vias. In some embodiments, thedielectric material of second routing area 106 a is a same dielectricmaterial as the dielectric material of ILV layers 160. In someembodiments, the conductive lines and/or vias of second routing area 106a are a same material as first routing area 104 a. In some embodiments,the conductive lines and/or vias of second routing area 106 a aredifferent from the material of the conductive lines and/or vias of firstrouting area 104 a. In some embodiments, the conductive vias of ILVlayers 160 include a same material as the conductive lines and/or viasof second routing area 106 a. In some embodiments, the conductive viasof ILV layers 160 include a different material from the conductive linesand/or vias of second routing area 106 a.

Third routing area 108 a is a dielectric material having conductivelines and/or vias formed therein. The conductive lines and or viasprovide electrical connections for signal transfer between third activecircuit block 108 and other components of chip layout 100. In someembodiments, third routing area 108 a includes conductive viasconfigured to electrically connect fourth active circuit block 110 tocentral processing chip 102. In some embodiments, third routing area 108a is configured to electrically connect ILV layer 160 between thirdactive circuit block 108 and second active layer 106 with ILV layer 160between the third active circuit block and fourth active circuit block110. In some embodiments, the dielectric material of third routing area108 a is a same material as the dielectric material of first routingarea 104 a and second routing area 106 a. In some embodiments, thedielectric material of third routing area 108 a is different from thedielectric material of at least one of first routing area 104 a orsecond routing area 106 a. In the embodiment of FIG. 4, the dielectricmaterial of third routing area 108 a is different from the dielectricmaterial of ILV layer 160, so that the dielectric materials act as etchstop layers during formation of the conductive lines and/or vias. Insome embodiments, the dielectric material of third routing area 108 a isa same dielectric material as the dielectric material of ILV layers 160.In some embodiments, the conductive lines and/or vias of third routingarea 108 a are a same material as first routing area 104 a and secondrouting area 106 a. In some embodiments, the conductive lines and/orvias of third routing area 108 a are different from the material of theconductive lines and/or vias of at least one of first routing area 104 aor second routing area 106 a. In some embodiments, the conductive viasof ILV layers 160 include a same material as the conductive lines and/orvias of third routing area 108 a. In some embodiments, the conductivevias of ILV layers 160 include a different material from the conductivelines and/or vias of third routing area 108 a.

Fourth routing area 110 a is a dielectric material having conductivelines and/or vias formed therein. The conductive lines and or viasprovide electrical connections for signal transfer between fourth activecircuit block 110 and other components of chip layout 100. In someembodiments, fourth routing area 110 a is configured to electricallyconnect to ILV layer 160 between third active circuit block 108 andfourth active layer 110. In some embodiments, the dielectric material offourth routing area 110 a is a same material as the dielectric materialof first routing area 104 a, second routing area 106 a and third routingarea 108 a. In some embodiments, the dielectric material of fourthrouting area 110 a is different from the dielectric material of at leastone of first routing area 104 a, second routing area 106 a or thirdactive circuit block 108 a. In the embodiment of FIG. 4, the dielectricmaterial of fourth routing area 110 a is different from the dielectricmaterial of ILV layer 160, so that the dielectric materials act as etchstop layers during formation of the conductive lines and/or vias. Insome embodiments, the dielectric material of fourth routing area 110 ais a same dielectric material as the dielectric material of ILV layers160. In some embodiments, the conductive lines and/or vias of fourthrouting area 110 a are a same material as first routing area 104 a,second routing area 106 a and third routing area 108 a. In someembodiments, the conductive lines and/or vias of fourth routing area 110a are different from the material of the conductive lines and/or vias ofat least one of first routing area 104 a, second routing area 106 a orthird routing area 108 a. In some embodiments, the conductive vias ofILV layers 160 include a same material as the conductive lines and/orvias of fourth routing area 110 a. In some embodiments, the conductivevias of ILV layers 160 include a different material from the conductivelines and/or vias of fourth routing area 110 a.

FIG. 4 also includes an enlarged cross sectional view of second routingarea 106 a. Second routing area 106 a includes a heat dissipationelement 170 at a surface of the second routing area distal from centralprocessing chip 102. Second routing area 106 a further includes powerlines 180 configured to provide power to second active circuit block106. In some embodiments, first routing area 104 a, third routing area108 a and fourth routing area 110 a include similar structures as secondrouting area 106 a.

Heat dissipation element 170 in second routing area 106 a is in thermalcontact with a second active circuit block 106. In some embodiments,heat dissipation element 170 in second routing area 106 a is in physicalcontact with second active circuit block 106. In some embodiments, heatdissipation element 170 contacts a sidewall of second active circuitblock 106. In some embodiments, heat dissipation element 170 contacts atop surface of second active circuit block 106. Heat dissipation element170 is configured to conduct heat generated by second active circuitblock 106 away from the second active circuit block and enable effectiveheat transfer along chip layout 100. Arrow 410 indicates heat flowtoward central processing chip 102 along chip layout 100 facilitated byheat dissipation element 170. Arrow 420 indicates heat flow towardfourth active circuit block 110 along chip layout 100 facilitated byheat dissipation element 170. In some embodiments, heat dissipationelement 170 includes copper, aluminum, alloys thereof or other suitablethermal conductive materials.

Power lines 180 are formed in the dielectric material of second routingarea 106 a. Power lines 180 are configured to provide electrical powerto second active circuit block 106. In some embodiments power lines 180include copper, aluminum, alloys thereof or other suitable thermalconductive materials. In some embodiments, power lines 180 are connectedto an external power supply. In some embodiments, power lines 180 areconnected to a power supply within chip layout 100.

Power lines 180 are capable of transferring a higher current than powerlines in packaging arrangements which route power lines between activeelements. Second routing area 106 a provides sufficient separationbetween active elements of active circuit block 106 and power lines 180to facilitate higher currents through the power lines without asignificant risk of interference with operation of the active elementsin the second active circuit block.

FIG. 5 is a cross sectional view of the stacked chip layout 100 inaccordance with one or more embodiments. FIG. 5 is the cross sectionview along line B-B of FIG. 2 in accordance with one or moreembodiments. In the arrangement of FIG. 5, chip layout 100 includes aheat dissipation element 190 over a top surface of fourth active circuitblock 110 and fourth routing area 110 a. Chip layout 100 furtherincludes a substrate SUB connected to a bottom surface of centralprocessing chip 102. First active circuit block 104 and second activecircuit block 106 are not visible in FIG. 5, but are still present inchip layout 100.

Arrows 510 indicate heat dissipation from third active circuit block 108through fourth routing area 110 a to heat dissipation element 190 andfrom the third active circuit block through second routing area 106 a,first routing area 104 a and central processing chip 102 to substrateSUB. The heat from third active circuit block 108 is then transferred toa surrounding environment by convective heat transfer, radiation heattransfer or other heat transfer methods.

Arrows 520 indicate heat dissipation from fourth active circuit block110 to heat dissipation element 190 and from the fourth active circuitblock through third routing area 108 a, second routing area 106 a, firstrouting area 104 a and central processing chip 102 to substrate SUB. Theheat from fourth active circuit block 110 is then transferred to asurrounding environment by convective heat transfer, radiation heattransfer or other heat transfer methods.

The arrangement of chip layout 100 is able to transfer heat in a mannerwhich reduces negative impacts of the heat on each active circuit blockby dispersing the heat generated by third active circuit block 108 andfourth active circuit block 110 to areas which are not above firstactive circuit block 104 and second active circuit block 106. Theresulting structure is able to operate with fewer errors in comparisonwith some other packaging arrangements.

FIG. 6 is a cross sectional view of the stacked chip layout 100including a central clocking tree in accordance with one or moreembodiments. Central processing chip 102 includes a phase locked loop(PLL) 610 configured to generate a global clock signal for synchronizingexecuted functions in chip layout 100. A clock tree 620 is configured totransfer to the global clock signal to each of first active circuitblock 104, second active circuit block 106, third active circuit block108 and fourth active circuit block 110. Clock tree 620 is formed infull overlap area 130 (FIG. 3). By forming clock tree 620 in fulloverlap area 130, a length of the clock tree is shorter in comparisonwith other packaging arrangements. The shorter clock tree reduces a riskof error in the global clock signal received by distance components,e.g., fourth active circuit block 110. The shorter clock tree alsoreduces delay and jitter in a clock tree signal in comparison with otherpackaging arrangements because an overall amount of resistance due toinherent resistance of a conductive material of the clock tree isreduced. In some embodiments, additional global broadcast signalsgenerated by central processing chip 102 are also transmitted to firstactive circuit block 104, second active circuit block 106, third activecircuit block 108 and fourth active circuit block 110 by conductivelines and vias formed in full overlap area 130.

FIG. 7A is a perspective view of electrical connections between variousactive circuit blocks of the stacked chip layout 100 in accordance withone or more embodiments. Chip layout 100 includes vias 710 electricallyconnecting first active circuit block 104 to second active circuit block106. Vias 710 are formed in partial overlap area 120 (FIG. 3) betweenfirst active circuit block 104 and second active circuit block 106. Vias710 extend through ILV layer 160 between first active circuit block 104and second active circuit block 106. By positioning vias 710 in partialoverlap area 120, a length of the vias is reduced in comparison withother packaging arrangements. The location of vias 710 in partialoverlap area 120 also reduces interference and cross talk between thevias and other interconnect structures, e.g., power lines 180 (FIG. 4),in chip layout 100. Also by providing vias 710 in partial overlap area120 a connection location of the vias to first active circuit block 104and second active circuit block 106 are located only along edges of thefirst active circuit block and the second active circuit block. Byhaving consistent connection locations for the active circuit blocks,design complexity decreases and production time and costs are reduced incomparison with other packaging arrangements.

FIG. 7B is a perspective view of electrical connections between variousactive circuit blocks of the stacked chip layout 100 in accordance withone or more embodiments. Chip layout 100 includes vias 720 electricallyconnecting third active circuit block 108 to second active circuit block106. Vias 720 are formed in partial overlap area 120 (FIG. 3) betweenthird active circuit block 108 and second active circuit block 106. Vias720 extend through ILV layer 160 between third active circuit block 108and second active circuit block 106. By positioning vias 720 in partialoverlap area 120, a length of the vias is reduced in comparison withother packaging arrangements. The location of vias 720 in partialoverlap area 120 also reduces interference and cross talk between thevias and other interconnect structures, e.g., power lines 180 (FIG. 4),in chip layout 100. Also by providing vias 720 in partial overlap area120 a connection location of the vias to third active circuit block 108and second active circuit block 106 are located only along edges of thethird active circuit block and the second active circuit block. Byhaving consistent connection locations in the active circuit blocks,design complexity decreases and production time and costs are reduced incomparison with other packaging arrangements.

FIG. 8A is a perspective view of electrical connections between variousactive circuit blocks of the stacked chip layout 100 in accordance withone or more embodiments. Chip layout 100 includes electricallyconnections 810 between fourth active circuit block 110 second activecircuit block 106. Electrical connections 810 include conductive linesand vias disposed in fourth routing area 110 a and conductive viasextending through third routing area 108 a. Electrical connections 810also pass through ILV layers 160 between fourth routing area 110 a andsecond active circuit block 106. Fourth active circuit block 110 doesnot include a partial overlap area 120 with second active circuit block106. Fourth active circuit block 110 only overlaps with second activecircuit block 106 in full overlap area 130. Electrical connections 810are routed around full overlap area 130 to avoid interference betweenthe electrical connections and signals routed in the full overlap area,e.g., clock tree 620 (FIG. 6). In the embodiment of FIG. 8, electricalconnections pass above third active circuit block 108. In someembodiments, electrical connections 810 pass above first active circuitblock 104. Electrical connections 810 do not pass through either firstactive circuit block 104 or third active circuit block 108 which reducesthe risk of interference with active elements in those active circuitblocks.

FIG. 8B is a cross sectional view of electrical connections 810 betweenfourth active circuit block 110 and second active circuit block 106 ofthe stacked chip layout 100 in accordance with one or more embodiments.Electrical connections 810 are routed through fourth routing area 110 ato a location above third routing area 108 a. Routing electricalconnections 810 to a position above third routing area 108 a reducesinterference with active elements in third active circuit block 108because a separation between the electrical connections and the thirdactive circuit block is greater than in other packaging arrangements.Electrical connections 810 also include vias extending from fourthrouting area 110 a through third routing area 108 a to second activecircuit block 106 passing through intervening ILV layers 160. A lengthof the electrical connections 810 is reduced with respect to a packagingsystem which connects active circuit blocks located all on a same plane,e.g., 2D packaging arrangements. The shorter length of electricalconnections 810 reduces the risk of error in signals transmitted alongthe electrical connections due to inherent resistance in the electricalconnections.

FIG. 9 is a perspective view of a stacked chip layout 900 includingeight active circuit blocks in accordance with one or more embodiments.Chip layout 900 includes eight active circuit block blocks 904-918positioned in over a central processing chip 902. The eight activecircuit blocks 904-918 are arranged using similar guidelines as in chiplayout 100. The eight active circuit blocks 904-918 are each arranged onseparate planes. Each active circuit block of active circuit blocks906-918 partially overlaps at least one of other of the active circuitblocks 904-916. None of the active circuit blocks 906-918 fully overlapsany of the active circuit blocks 904-916. A full overlap area existswere a portion of each of active circuit blocks 904-918 overlap withevery other of the active circuit blocks 904-918, similar to fulloverlap area 130 of chip layout 100.

A size of active circuit blocks 904-918 is similar to the size of theactive circuit blocks of chip layout 100. The increased number of activecircuit blocks in chip layout 900 results in a greater amount of overlapwith other active circuit blocks.

A non-limiting example of placement of active circuit blocks 904-918includes placing a first active circuit block 904 in a location alignedwith a first corner of central processing chip 902 at an intersection ofa first edge and a second edge the central processing chip. A secondactive circuit block 906 is aligned with the first edge of centralprocessing chip 902. Second active circuit block 906 does not extend toa second corner of central processing chip 902 at an intersection of thesecond edge and a third edge of the central processing chip. A thirdactive circuit block 908 is located in a third corner of centralprocessing chip 902 at an intersection of the third edge and a fourthedge of the central processing chip. A fourth active circuit block 910is aligned with the fourth edge of central processing chip 902. Fourthactive circuit block 910 does not extend to a fourth corner of centralprocessing chip 902 at an intersection of the first edge and the fourthedge. A fifth active circuit block 912 is aligned with the fourth edgeof central processing chip 902, but does not extend to the first cornerof the central processing chip. A sixth active circuit block 914 isaligned with the second corner of central processing chip 902. A seventhactive circuit block 916 is aligned with the third edge of centralprocessing chip 902, but does not extend to the third corner of thecentral processing chip. An eighth active circuit block 918 is alignedwith the fourth corner of central processing chip 902.

Routing areas corresponding to each of active circuit blocks 904-918 arenot shown for the sake of simplicity. However, the routing areas arepresent in chip layout 900 to provide a routing path between variousactive circuit blocks 904-918 which avoid passing electrical connectionsthrough other active circuit blocks.

FIG. 10 is a perspective view of a stacked chip layout 1000 includingeight active circuit blocks in accordance with one or more embodiments.Chip layout 10000 includes eight active circuit block blocks 1004-1018positioned in over a central processing chip 1002. The eight activecircuit blocks 1004-1018 are arranged using similar guidelines as inchip layout 100. The eight active circuit blocks 1004-1018 are eacharranged on separate planes. Each active circuit block of active circuitblocks 1006-1018 partially overlaps at least one of other of the activecircuit blocks 1004-1016. None of the active circuit blocks 1006-1018fully overlaps any of the active circuit blocks 1004-1016. A fulloverlap area exists were a portion of each of active circuit blocks1004-1018 overlap with every other of the active circuit blocks1004-1018, similar to full overlap area 130 of chip layout 100.

A size of active circuit blocks 1004-1018 is smaller in comparison withthe size of the active circuit blocks of chip layout 100 and chip layout900. The reduced size of active circuit blocks 1004-1018 results in adecreased amount of overlap between the active circuit blocks incomparison with chip layout 900.

A non-limiting example of placement of active circuit blocks 1004-1018includes placing a first active circuit block 1004 in a location alignedwith a first corner of central processing chip 1002 at an intersectionof a first edge and a second edge the central processing chip. A secondactive circuit block 1006 is aligned with the first edge of centralprocessing chip 902. Second active circuit block 1006 does not extend toa second corner of central processing chip 1002 at an intersection ofthe second edge and a third edge of the central processing chip. A thirdactive circuit block 1008 is located in the second corner of centralprocessing chip 1002. A fourth active circuit block 1010 is aligned withthe third edge of central processing chip 1002. Fourth active circuitblock 1010 does not extend to a third corner of central processing chip1002 at an intersection of the third edge and a fourth edge of thecentral processing chip. A fifth active circuit block 1012 is alignedwith the third corner of central processing chip 1002. A sixth activecircuit block 1014 is aligned with the fourth edge of central processingchip 1002, but does not extend to a fourth corner of the centralprocessing chip at an intersection of the first edge and the fourth edgeof the central processing chip. A seventh active circuit block 1016 isaligned with the fourth corner of central processing chip 1002. Aneighth active circuit block 1018 is aligned with the fourth edge ofcentral processing chip 902, but does not extend to the first corner ofthe central processing chip.

Routing areas corresponding to each of active circuit blocks 1004-1018are not shown for the sake of simplicity. However, the routing areas arepresent in chip layout 1000 to provide a routing path between variousactive circuit blocks 1004-1018 which avoid passing electricalconnections through other active circuit blocks.

FIG. 11 is a flow chart of a method 1100 of making a stacked chip layoutin accordance with one or more embodiments. Method 1100 begins withoperation 1102 in which an active circuit block is formed using anoriginal size of the active circuit block. The active circuit blockformed in operation 1102 is not subjected to an artificial increase insize to provide additional space for routing of electrical connectionsbetween active circuit blocks. In some embodiments, the active circuitblock is a memory device or an ASIC device, e.g., first active circuitblock 104 (FIG. 1).

Method 1100 continues with operation 1104 in which the active circuitblock is placed on a chip. An area of the chip is greater than an areaof the active circuit block. In some embodiments, the chip is a centralprocessing chip, e.g., central processing chip 102 (FIG. 1). In someembodiments, placing the active circuit block on the chip includeselectrically connecting the active circuit block to the chip. In someembodiments, an ILV layer is formed on the chip prior to placing theactive circuit block on the chip, and the active circuit block iselectrically connected to the chip through the ILV layer.

In some embodiments, the active circuit block is bonded to the chipusing solder balls, copper posts or other suitable connection elements.In some embodiments, a molding material or underfill material is used toincrease a mechanical strength of the bond between the active circuitblock and the chip.

In operation 1106 a routing area is formed around the active circuitblock so that a combined area of the active circuit block and therouting area match the area of the chip. In some embodiments, therouting area includes a dielectric material. In some embodiments, therouting area is formed by physical vapor deposition (PVD), chemicalvapor deposition (CVD), atomic layer deposition (ALD), an epitaxialprocess, or other formation processes. In some embodiments, the routingarea includes a multi-layer element.

In some embodiments, openings for conductive lines and/or vias areformed in the routing area. In some embodiments, the openings are forpower lines for providing power to the active circuit block. In someembodiments, the openings are formed using a photolithography andetching process. In some embodiments, the openings are formed using adual damascene process. The openings are then filled with a conductivematerial to form conductive lines and/or vias to provide electricalconnections for the active circuit block and subsequently added activecircuit blocks. In some embodiments, the conductive material is formedby sputtering, PVD, ALD, electroplating or other suitable formationmethods. In some embodiments, a planarizing process, e.g., chemicalmechanical polishing (CMP), is performed to remove excess conductivematerial following filling the openings.

Method 1100 continues with operation 1108 in which a heat dissipationelement is formed over the routing area. In some embodiments, the heatdissipation element includes copper, aluminum, alloys thereof or othersuitable thermally conductive materials. In some embodiments, the heatdissipation element is formed over both the active circuit block and therouting area. In some embodiments, the heat dissipation element contactsa sidewall of the active circuit block. In some embodiments, the heatdissipation element is formed by sputtering, PVD, ALD, electroplating orother suitable formation methods.

In operation 1110 an inter-level via (ILV) layer is formed over theactive circuit block. The ILV layer is formed over the routing area aswell as the active circuit block. The ILV layer is a dielectric layer inwhich vias are formed to provide electrical connection between variousactive circuit blocks. In some embodiments, a material of ILV layer isdifferent from a material of the routing area, so that the routing areaacts as an etch stop during formation of via openings in the ILV layer.Similarly, the ILV layer can act as an etch stop during formation of theopenings in the routing area. In some embodiments, the ILV layer isformed by PVD, CVD, ALD, an epitaxial process or another suitableformation method.

In some embodiments, the via openings in the ILV layer are formed by acombination of photolithography and etching processes. The via openingsare then filled with a conductive material to form conductive vias toprovide electrical connections for the active circuit block andsubsequently added active circuit blocks. In some embodiments, theconductive material is formed by sputtering, PVD, ALD, electroplating orother suitable formation methods. In some embodiments, a planarizingprocess, e.g., CMP, is performed to remove excess conductive materialfollowing filling the via openings.

Method 1100 continues with operation 1112 in which another activecircuit block is placed on the ILV layer. The other active circuit blockpartially overlaps with prior placed active circuit blocks, but does notfully overlap with the prior placed active circuit blocks. In someembodiments, the active circuit block is bonded to the chip using solderballs, copper posts or other suitable connection elements. In someembodiments, a molding material or underfill material is used toincrease a mechanical strength of the bond between the active circuitblock and the chip. In some embodiments, the connection elements andmethod in operation 1112 are the same as the connection elements andmethod in operation 1104. In some embodiments, the connection elementsor method in operation 1112 is different from the connection elements ormethod in operation 1104.

In operation 1114 connects for a clock tree and broadcast signals areformed in a full overlap area. The full overlap area, e.g., full overlaparea 130 (FIG. 3), is a location where all active circuit blocks overlapwith one another. In some embodiments, the clock tree, e.g., clock tree620 (FIG. 6), and broadcast signal lines are formed in the full overlaparea by a combined photolithography and etching process followed by ametallization and planarization process.

One aspect of this description a stacked chip layout. The stacked chiplayout includes a central processing chip; and a first active circuitblock over the central processing chip. The stacked chip layout furtherincludes a second active circuit block over the first active circuit. Acenter of the second active circuit block is offset from a center of thefirst active circuit block, the second active circuit block overlaps thefirst active circuit block in a partial overlap area, and the secondactive circuit block exposes a portion of the first active circuitblock. The stacked chip layout further includes a local conductiveelement electrically connecting the first active circuit block to thesecond active circuit block. The local conductive element is within thepartial overlap area.

Another aspect of this description relates to a stacked chip layout. Thestacked chip layout includes a central processing chip; and a firstactive circuit block over the central processing chip. The stacked chiplayout further includes a second active circuit block over the firstactive circuit, wherein the second active circuit block overlaps thefirst active circuit block. The stacked chip layout further includes afirst routing region on a same plane as the second active circuit block.The stacked chip layout further includes a second routing region betweenthe first routing region and the first active circuit block. The stackedchip layout further includes a local conductive element electricallyconnecting the first active circuit block to the second active circuitblock. The local conductive element extends through the first routingregion and the second routing region.

Still another aspect of this description relates to a method of making astacked chip layout. The method includes placing a plurality of activecircuit blocks over a central processing chip. The central processingchip has a first area, and each active circuit block of the plurality ofactive circuit blocks has an area less than the first area. The methodfurther includes forming a plurality of routing regions over the centralprocessing chip. Each routing region corresponds to an active circuitblock of the plurality of active circuit blocks, and at least onerouting region of the plurality of routing regions overlaps with atleast another routing region of the plurality of routing regions.

It will be readily seen by one of ordinary skill in the art that thedisclosed embodiments fulfill one or more of the advantages set forthabove. After reading the foregoing specification, one of ordinary skillwill be able to affect various changes, substitutions of equivalents andvarious other embodiments as broadly disclosed herein. It is thereforeintended that the protection granted hereon be limited only by thedefinition contained in the appended claims and equivalents thereof.

What is claimed is:
 1. A stacked chip layout comprising: a centralprocessing chip; a first active circuit block over the centralprocessing chip; a second active circuit block over the first activecircuit block, wherein a center of the second active circuit block isoffset from a center of the first active circuit block in two directionparallel to a top surface of the central processing chip, the secondactive circuit block overlaps the first active circuit block in apartial overlap area, and the second active circuit block exposes aportion of the first active circuit block; and a local conductiveelement electrically connecting the first active circuit block to thesecond active circuit block, wherein the local conductive element iswithin the partial overlap area.
 2. The stacked chip layout of claim 1,wherein the local conductive element extends in a directionperpendicular to a direction of the offset between the center of thefirst active circuit block and the center of the second active circuitblock.
 3. The stacked chip layout of claim 1, further comprising adielectric layer between the first active circuit block and the secondactive circuit block.
 4. The stacked chip layout of claim 3, wherein thelocal conductive element extends through the dielectric layer.
 5. Thestacked chip layout of claim 1, further comprising a third activecircuit block over the second active circuit block, wherein a firstportion of the third active circuit block overlaps both the first activecircuit block and the second active circuit block in a full overlapregion.
 6. The stacked chip layout of claim 5, wherein the localconductive element in outside of the full overlap region.
 7. The stackedchip layout of claim 5, further comprising an additional localconductive element electrically connecting a second portion of the thirdactive circuit block to the first active circuit block, wherein thesecond portion of the third active circuit block overlaps the firstactive circuit block, and the second portion is outside of the fulloverlap region.
 8. The stacked chip layout of claim 7, wherein theadditional local conductive element comprises: a first segment extendingparallel to a direction of the offset from the center of the firstactive circuit block to the center of the second active circuit block;and a second segment extending perpendicular to the direction of theoffset from the center of the first active circuit block to the centerof the second active circuit block.
 9. The stacked chip layout of claim5, further comprising an additional local conductive elementelectrically connecting a second portion of the third active circuitblock to the first active circuit block, wherein the second portion ofthe third active circuit block exposes the first active circuit block,and the second portion is outside of the full overlap region.
 10. Astacked chip layout comprising: a central processing chip; a firstactive circuit block over the central processing chip; a second activecircuit block over the first active circuit block, wherein the secondactive circuit block overlaps the first active circuit block, and boththe first active circuit block and the second active circuit block arewithin a perimeter of the central processing chip in a plan view; afirst routing region on a same plane as the second active circuit block;a second routing region between the first routing region and the firstactive circuit block; and a local conductive element electricallyconnecting the first active circuit block to the second active circuitblock, wherein the local conductive element extends through the firstrouting region and the second routing region.
 11. The stacked chiplayout of claim 10, further comprising: a first dielectric layer in thefirst routing region, wherein the local conductive element extendsthrough the first dielectric layer; and a second dielectric layer in thesecond routing region, wherein the local conductive element extendsthrough the second dielectric layer.
 12. The stacked chip layout ofclaim 10, wherein the local conductive element is connected to thesecond active circuit block in a region outside of a portion of thesecond active circuit block that overlaps the first active circuitblock.
 13. The stacked chip layout of claim 10, further comprising athird active circuit block between the first active circuit block andthe second active circuit block.
 14. The stacked chip layout of claim13, wherein the local conductive element is isolated from the thirdactive circuit block.
 15. The stacked chip layout of claim 13, furthercomprising a full overlap region where the second active circuit blockoverlaps both the third active circuit block and the first activecircuit block.
 16. The stacked chip layout of claim 15, furthercomprising a global conductive element electrically connected to thefirst active circuit block, the second active circuit block and thethird active circuit block, wherein the global conductive element is inthe full overlap region.
 17. A stacked chip layout comprising: a centralprocessing chip; a first active circuit block over the centralprocessing chip; a second active circuit block over the first activecircuit block, wherein the second active circuit block overlaps thefirst active circuit block in a partial overlap area, the second activecircuit block exposes a portion of the first active circuit block, andthe second active circuit block extends beyond at least one edge of thefirst active circuit block in a plan view; and a local conductiveelement electrically connecting the first active circuit block to thesecond active circuit block, wherein at least a portion of the localconductive element is within the partial overlap area, and the localconductive element is isolated from the central processing chip.
 18. Thestacked chip layout of claim 17, wherein the central processing chipcomprises a phase locked loop.
 19. The stacked chip layout of claim 18,further comprising a global conductive element electrically connectingthe first active circuit block, the second active circuit block and thephase locked loop.
 20. The stacked chip layout of claim 19, wherein theglobal conductive element is located in a full overlap area, and thefull overlap area is a region where the partial overlap area overlapsthe central processing chip.